The present invention relates to a soft magnetic thin film and a magnetic recording head using the same.
In a magnetic recording head for a hard disk, an upper magnetic pole has thickness of 3-4 μm and a step-shaped part so as to generate enough magnetic fluxes at a front end. Therefore, the upper magnetic pole is formed by a plating method, which has high deposition efficiency and which is good for selective film formation.
To improve recording density, a material having high saturation magnetic flux density (Bs) is required for a material of magnetic poles of the recording head.
A process of producing a plated film made of a FeCo alloy having high Bs and its characteristics are disclosed in Japanese Patent Gazette No. 2002-280217 (Doc. 1).
In Japanese Patent Gazette No. 2004-127479A (Doc. 2), a base layer made of Ru is used so as to improve soft magnetic characteristics of a FeCoNi alloy.
Further, in Japanese Patent Gazette No. 2005-86012 (Doc. 3), intensity ratio of bcc (211) and bcc (110) is controlled so as to improve soft magnetic characteristics of a FeCo alloy film having Bs>2.3 T (T: tesla).
The Bs of the plated film of Doc. 1 is greater than that of conventional ones, but magnetostriction is great. Therefore, it is difficult to improve soft magnetic characteristics, and a coercive force is great. If the coercive force is great, high frequency response is made worse. Thus, the coercive force must be minimized.
In Doc. 2, the FeCoNi alloy includes Ni, so the Bs of the plated film is reduced to less than 2.3 T. Therefore, a soft-magnetized FeCo alloy having the Bs of 2.3 T or more is required.
In Doc. 3, the Bs is 2.3 T or more, but a NiFe material is required as a base layer. Further, it is difficult to control crystal orientation due to narrow margins.